What We Found When We Tried to Blow Up a Can of Expanding Foam

Introduction

I love blowing things up. I’m not talking about actual explosives, though those are fun too. No, I’m talking about things like mixing up a batch of expanding foam and then dumping it into a container to see what happens. And when I say “a batch”, I actually mean 4 gallons of foam mix and 2 gallons of water, or something like that. So last week when my friends at the hardware store asked me for help in testing out some new materials for their expanding foam kits, naturally I jumped at the chance to get my hands on some chemicals to play with. To be fair, it was kind of an excuse for me to do something really stupid and destructive that would also have positive results. We were going to test out some new materials as well as different recipes for the expanding foam mix. The goal was simple: how can we make this stuff grow faster and bigger?

The intent here is to mix a few gallons of foam, find a suitable container for the foam to expand within, and then time it.

While this is the ideal situation, there are other options to work with. You can use a few gallons of foam and place it in a trash can. Another option is using a 32 gallon trash can.

You’ll need to drill holes through the sides of the trash can so that when you pour in your expanding foam solution, air will have somewhere to escape from as well.

When mixing up your solution for use with an expanding foam sprayer, I recommend using TSP cleaner (trisodium phosphate), which acts as an acid and helps break down dirt on surfaces during cleaning processes such as ovens or bathrooms.[1]

The container will be a 32 gallon trash can.

The container will be a 32 gallon trash can, which is a standard size sold at hardware stores everywhere. According to our measurements, it has an internal diameter of 12 inches and a height of 21 inches.

The cans we’ve seen on the market are all similar in shape and size, with the exception of one or two cans that are slightly taller. Unfortunately, they’re also all metal—so there’s no way to see through them without first cutting them open (and even then, you’d only get to look at what’s underneath). If you have access to an empty garbage can from your local waste management company or other source (like the recycling bin of someone who doesn’t care about privacy), it might be worth trying this experiment with something else before buying a new trash can for yourself—but if not, these dimensions should work well enough for most people’s purposes!

We cut the bottom off of the trash can and set it aside. Then we drilled some holes in the sides at the top, so that we could run some electrical wire through them.

After that, we connected our speaker to an amplifier and ran power cables out of the amplifier to a couple of outlets. We also connected a USB cable from your computer or other device to a laptop inside of your canister for sound effects if you want them (we did).

Then I started on the foam. I added 3 gallons of water to the trash can with 6 ounces of TSP (trisodium phosphate) cleaner (you want to use something that is safe for aluminum). TSP is used as a heavy cleaner in many prepackaged mixes you can buy from hardware stores. It’s more expensive than laundry powder, but not too much more than powdered dishwasher detergent (which doesn’t contain phosphate), and it does clean better than either of those things.

This is a perfect example of how to use TSP as a heavy cleaner in many prepackaged mixes you can buy from hardware stores. You want to use something that is safe for aluminum. TSP is used as a heavy cleaner in many prepackaged mixes you can buy from hardware stores. It’s more expensive than laundry powder, but not too much more than powdered dishwasher detergent (which doesn’t contain phosphate), and it does clean better than either of those things.

I mixed up some more foam mix and poured it into our trash can ‘pool’. I turned on the radio, grabbed a book and spent two hours watching my expanding foam pool do not very much at all except grow very slowly and froth a lot, while listening to mix tapes on 8tracks.com.

To get started, you’ll need a large trash can. Any size will do really, but to make sure that the pool stays contained we chose a large 30 gallon trash can. Next up is the recipe: one part water (1/2 cup), one part dish soap (2 tablespoons) and three parts TSP (3 cups). Now mix it all together in your bucket until it’s fully dissolved.

Then pour the mixture into your container of choice!

Conclusion

I’ve tried to analyze this phenomenon and have come up with a few theories. The first theory is that my foam just didn’t have enough air in it. I used a cheap brand at the time, and got a bit impatient when mixing up the foam, so I didn’t get all the bubbles out of it before pouring it into the trash can. (And if you really want to see what happens when you carefully mix up your foam and pour it into a sealed container, check out this video.) Another theory is that either my can wasn’t big enough or that there were two factors at play here: one being temperature (the temperature was about 35 degrees Farenheit), and another being humidity (the humidity was hovering around 70%). For example, if your can isn’t big enough or if there isn’t enough air in your mix to begin with, then your foam will just slowly grow and grow until it reaches its maximum density.